sub-feed lugs

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Colvin Jones Davis

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I have a situation with a 125A MLO load center fed out of a 100A breaker in a main distribution panel. The load center is located in a condo unit and feeds all of the circuits in the main condo unit and in an adjacent "lock-off" room. The lock-off room can be rented separately from the main condo unit, and the code official is requiring that it has its own load center.

I have found a sub-feed lug kit which can be installed in the main load center to feed another load center in the lock-off room. Since I am actually tapping the bus bars of the main panel (not tapping the conductors), does this installation fall under the tap rule 240.21(B)(1)? Also, does the sub-fed panel require a main circuit breaker, or can I make it MLO and comply with 408.36(A), Exception No. 1? Is there a section in the NEC that covers sub-feed and/or feed-thru lugs in panels?
 
Colvin Jones Davis said:
The lock-off room can be rented separately from the main condo unit, and the code official is requiring that it has its own load center.
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This sounds like a local building code and/or zoning code, and/or a "condo association bylaw" issue.

If the rent is being paid to the owner of the condo from which the power is supplied, in my area, the owner of the condo can include the fee for the power in the rent.
 
Don,

I understand that if this situation falls under the 10' tap rule, I have to have a MCB on the sub-fed panel. However, I am not sure if the tap rules apply to this case, since I am tapping the busses on the first panel.

I have had situations before where I use feed-thru lugs on a panel to serve an adjacent panel. In this case, both panels have the same amp rating and I am not required to have a MCB in the second panel....correct?
 
Al,

This is a time-share condo / hotel situation where the electric is not metered separately for each condo unit. The building owner pays the utilities and includes the cost in the time-share fees or rent.

The code official is requiring separate panels, because he does not feel that we comply with 240.24(B) Exception No. 2 (access to OC devices).
 
The first basic concept is that all conductors must be protected at their ampacity. The second basic concept is that that protection must be located at the beginning of the run, at the place where the conductors get their power. The tap rules give us exceptions to concept number two. They allow us to protect conductors at the end of the run, at the load side, under certain specific circumstances.

What you are suggesting, if I understand correctly, is that these conductors will not be protected at their origin, given that they are connected to the bus work of the main panel, and that they will not be protected at their end point, given that you want to use an MLO panel. How, then, do you propose to protect the conductors?
 
Charlie b,

See my comments to Don. I am protecting the conductors at their origin with a breaker at the MDP. By using the sub-feed lug kit, the two panels are essentially one, correct?
 
What size wire will you run to this Storage Room Panel? If it is #3, then it sounds like all is in order since the 100 amp main will be protecting both panels and both feeders.
 
CJD,
See my comments to Don. I am protecting the conductors at their origin with a breaker at the MDP. By using the sub-feed lug kit, the two panels are essentially one, correct?
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If the conductors are protected on the line side at or below their ampacity they are not taps. If they are taps, then they must have overcurrent protection at the load end. That would prevent them from terminating at a MLO. Also the panel will require protection per 408.36(A).
Don
 
Colvin,

What you propose is fine. 100a main cb, feeds a 100a panel with feed thru

lugs to a 2nd 100a mlo panel, all feeders are rated 100a or greater.

There are no taps with this setup because all the feeders are the same size.

408.36(A) ex.1
 
Colvin Jones Davis said:
Charlie b,

See my comments to Don. I am protecting the conductors at their origin with a breaker at the MDP. By using the sub-feed lug kit, the two panels are essentially one, correct?
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I agree. I just don't see what the objection is.
 
Bob,
I agree. I just don't see what the objection is.
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The original poster asked about the tap rules and no where does he say what size conductors are being used between the two panels. If the conductors are tap conductors (per the NEC definition) then overcurrent protection is required at the load end.
Don
 
don_resqcapt19 said:
The original poster asked about the tap rules and no where does he say what size conductors are being used between the two panels. If the conductors are tap conductors (per the NEC definition) then overcurrent protection is required at the load end.
Don
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The OP asked if his conductors should be covered under the tap rules - to which the answer is a firm maybe.

This sounds like semantics. brought on by the way the NEC uses the word tapped to mean a reduced size connection and the common trade practice of a tap being any connection.

If the conductors between the panels are properly protected by the OCPD feeding the first panel, then they are protected "at the point where they receive their supply" and the tap rules in 240.21 do not apply.
 
Jim,
This sounds like semantics. brought on by the way the NEC uses the word tapped to mean a reduced size connection and the common trade practice of a tap being any connection.
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When asking code questions you have to use code language, not field language. This is one of the big problems with the code. A word means one thing in the everyday field use and something different in the code rules.
Even the CMPs get caught up in this sometimes. One example is the word fitting. In the field the word fitting is often used to mean conduit body. For years the code said that you were permitted an maximum of 360?s of bend between "fittings". Of course they really meant conduit body, not fitting as a coupling is a fitting, but for years the code rules permitted 360?s of bend between each coupling.
Don
 
don_resqcapt19 said:
When asking code questions you have to use code language, not field language. This is one of the big problems with the code. A word means one thing in the everyday field use and something different in the code rules.
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And when replying, we need to make sure we understand the real question. Sometimes this results in many questions back towards the OP which can lead to them thinking we are being un-cooperative.
 
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